I have a early version TCI 4 link rear on my 66. Mostly street driven, but is now seeing some drag strip time! It currently has the original non-adjustable Aldan shocks, and from the info I've gathered, probably 250lb rate springs. I'm going to upgrade to a set of double adjustable AFCO shocks and I'm thinking of softening up the rear some. It's always been a bit too stiff feeling for my taste, so I'm thinking about going to a 200lb. spring. I understand they are also now shipping these kits with 10" springs, so I may look at those also. Right now, after the initial launch the rear feels like its almost immediately unloading. The goal is a harder launch and keep the rear planted. Any suggestions on changing the spring rate and shock tuning tips?